Core rod stopping and releasing device in a powder material forming press

ABSTRACT

A STOPPING AND RELEASING DEVICE FOR A CORE ROD EMPLOYED IN A POWDER MATERIAL FORMING PRESS WHENEVER AN ARTICLE HAVING A STEPPED HOLD IS PRODUCED FROM A POWDER MATERIAL COMPRISES A PLUALITY OF RADIALLY DISPLACEABLE CATCHES EACH HAVING A RADIALLY INWARDLY EXTENDED TONGUE-LIKE PORTION AND A RADIALLY OUWARDLY LOCATED RISING PORTION OF A PREDETERMINED HEIGHT. MEANS ARE PROVIDED FOR DISPLACING THE PLURALITY OF CATCHES RADIALLY INWARDLY, THE CORE ROD IS RELEASED FOR A PREDETERMINED DISTANCE UNTIL IT IS SUPPORTED BY THE RADIALLY INWARDLY EXTENDED TONGUE-LIKE PORTIONS OF THE CATCHES.

June 20, 1972 EIHARA ETAL 3,6

CORE ROD STOPPING AND RELEASING DEVICE IN A POWDER MATERIAL FORMING PRESS Filed July 23, 1970 3 Sheets-Sheet 1 Fl. 5 2 I Elm/ARA EIAL 3,671,164 CORE ROD STOPPING AND RELEASING DEVICE IN A POWDER MATERIAL FORMING PRESS S Sheets-Sheet 2 June 20, 1972 Filed July 23, 1970 June 20, 1972 El HARA ETAL 3,671,164

CORE ROD STOPPING AND RELEASING DEVICE IN A POWDER MATERIAL FORMING PRESS Filed July 25, 1970 3 Sheets-Sheet 5 United States Patent Filed July 23, 1970, Ser. No. 57,695 Claims priority, application Japan, Sept. 29, 1969, 44/ 77,304 Int. Cl. 133% 11/02, 15/00 US. Cl. 425-414 4 Claims ABSTRACT OF THE DISCLOSURE A stopping and releasing device for a core rod employed in a powder material forming press whenever an article having a stepped hole is produced from a powder material comprises a plurality of radially displaceable catches each having a radially inwardly extended tongue-like portion and a radially outwardly located rising portion of a predetermined height. Means are pro vided for displacing the plurality of catches radially inwardly or outwardly, whereby When the plurality of catches are displaced radially inwardly, the core rod is stopped by the upper ends of the rising portions of the catches, and when the catches are displaced radially outwardly, the core rod is released for a predetermined distance until it is supported by the radially inwardly extended tongue-like portions of the catches.

BACKGROUND OF THE INVENTION This invention relates to powder compacting and forming presses and more particularly to a stop and release device for a core rod employed in a powder material forming press.

Articles of various kinds and shapes made of powder materials are widely employed in industrial applications. Of these articles, those having a centrally located hole of a stepped configuration, as in the case of a powder formed pot having a central hole at the bottom, are manufactured through the use of a core rod also having a stepped configuration conforming to that of the articles. Since the stepped annular surface portion of the core rod receives, at the time of compacting of the powder material, a part of compressive force applied to the powder material, the core rod must be supported at a desired position under a suflicient force for counteracting the above described force.

In addition, since the powder formed article thus compacted must be removed from a die, the die supported by a movable platen is first lowered to the position aligning the upper surface of a fixed lower punch, and the core rod is thereafter forced down by a predetermined distance from the above described stop position.

SUMMARY OF THE INVENTION Therefore, the primary object of the present invention is to provide a novel stopping and releasing device for a core rod which can withstand the part of the compressive force applied to the stepped portion of the core rod when the device is at the stop position, and permits descent of the core rod precisely by a predetermined distance when it is desired to take the article thus compacted out of the die.

Another object of the present invention is to provide a novel stopping and releasing device wherein the stopping position and hence the releasing position can be adjusted in accordance with the size of the article to be formed from the powder material.

These and other objects of the present invention can "ice be achieved by a novel construction of the stopping and releasing device for a core rod which comprises a plurality of radially displaceable catches each having a radially inwardly extended tongue-like portion and a radially outwardly located rising portion of a predetermined height, and means for displacing the catches radially outwardly or inwardly, whereby when the plurality of catches are displaced radially inwardly, the core rod is stopped by the upper ends of the rising portions of the catches, and when the catches are displaced radially outwardly, the core rod is released for a predetermined distance until it is supported by the radially inwardly extended tonguelike portions of said catches.

The nature, principle, and utility of the present inven tion will be better understood from the following detailed description with respect to a preferred embodiment thereof when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS In the drawings:

FIG. 1 is an elevational view in section of a stopping and releasing device according to the present invention;

FIG. 2 is a cross sectional view of the stopping and releasing device taken along the line II-II in FIG. 1, as viewed in the arrow direction;

FIG. 3 is a fragmentary sectional view of catches employed in the stopping and releasing device taken along the line III-III in FIG. 2, as viewed in the arrow direction;

FIGS. 4(a) and 4(b) are a plan view and a side view in section, respectively, of a rotating cam for operating the plurality of catches shown in FIGS. 2 and 3;

FIG. 5 is a cross sectional view of a reversible hydraulic motor for driving the rotating cam taken along the line VV in FIG. 1, as viewed in the arrow direction; and

FIGS. 6 through 9 are schematic elevational views, in vertical section, for explaining the sequence of operational steps of a powder material forming press wherein the stopping and releasing device according to the present invention is employed.

DETAILED DESCRIPTION OF INVENTION Referring to FIG. 1 showing one part of a powder material forming press (which is in a condition wherein a power material occupies a space formed within a die D and above a lower punch LP, and the core rod 2 is at its highest position as indicated in FIG. 6 which will hereinafter be referred to), there is indicated a piston rod 3 rigidly connected to a core rod 2 and extending downwardly through the central portion of a cover 1. At an intermediate portion of the piston rod 3, a piston 4 is integrally formed and is adapted to operate slidably within a cylinder 5. Passages or pipe lines 51 and 52 are led to the upper and lower sides of the piston 4 inside the cylinder 5, respectively, so that compressed air can be supplied or exhausted through these passages or pipe lines 51 and 52.

To the lower end of the piston rod 3, a circular block 6 heat-treated for high hardness is fixed by means of machine screws. Around the lower portion of the piston rod 3, an upper-limit setting sleeve 7 is provided so that the piston rod 3 can slide freely inside of the sleeve 7, and the downwardly facing end surface of the upper limit setting sleeve 7 can abut the upwardly facing surface of the circular block 6. One end 71 of an arm extending laterally from the upper limit setting sleeve 7 is loosely fitted around a vertical shaft 14 provided inside a casing 1' rigidly connected to the cover 1 so that the rotation of the upper limit setting sleeve 7 is prevented. The outer surface of the sleeve 7 is threaded and engaged with an 3 internally threaded adjusting ring 8. The adjusting ring 8 is provided at its lower circumferential portion with a gear wheel 81 which is meshed with a pinion 9 fixedly mounted on a shaft 10. On the upper end of the shaft 10 is provided a bevel gear 11 which is meshed with another bevel gear 12 coupled to an upper limit adjusting shaft 13.

With the above described arrangement, when the upper limit adjusting shaft 13 is rotated, the pinion 9 is rotated through the bevel gears 12 and 11, whereby the adjusting ring 8 is rotated. Rotation of the adjusting ring 8 causes a vertical movement of the upper limit adjusting sleeve 7, and the upper limit of the piston rod 3 and, hence, the upper limit of the core rod 2 are thereby adjusted. Generally, the upper limit of the movement of the core rod 2 is set at a position at which the upper end of the core rod 3 is brought into alignment with the upper surface plane of the die D (see FIG. 6).

Downwardly spaced apart from the lower surface of the circular block 6 by a predetermined distance a, there is provided a stop and release device according to the present invention. This device comprises a plurality of catches or wedge blocks 16 each having an arcuate rising portion 16a and a horizontally extended tongue-like portion 15. Furthermore, the catches 16 are radially guided by confronting surfaces of adjacently disposed guiding blocks 17 so that they can be moved radially inwardly or radially outwardly.

When the plurality of catches (three catches are shown) are advanced radially inwardly as shown in FIG. 2, the inner diameter of an inside bore (shown by the full lines) formed by the arcuate inwardly facing surfaces or walls of the rising or upstanding portions 16a of the catches 16 is smaller than the diameter of the circular block 6, and, when the plurality of catches are retracted radially outwardly, the inner diameter of the inside bore (shown by the chain lines in FIG. 2) is larger than the diameter of the circular block 6. The depth of the inside bore thus formed is denoted by b in FIG. 1.

On the lower surface of the tongue portion of each of the catches 16, a short pin 18 is implanted, on which a roller 19 is rotatably mounted. Each of the rollers 19 is loosely inserted into one of spirally disposed cam grooves 21 cut on the upper surface of a oscillatable cam 20. Since the arrangement of the spirally disposed grooves 21 is as indicated in FIG. 4(a), the catches 16 are radially advanced or retracted through the rollers 19 when the oscillatable cam is rotated through a predetermined angle, and the diameter of the inner bore formed by the arcuate rising portions 16a of the catches 16 can be varied.

On the inside surface of a central hole provided through the oscillatable cam 20, splines 22 are cut, and a splined shaft 24 of a reversible motor 23, such as a hydraulic motor, is engaged in the splined hole. By means of the spline coupling between the oscillatable cam 20 and the reversible motor shaft 24, the oscillatable cam 20 can be driven by the motor 23 irrespective of the up-and-down displacement of the oscillatable cam for the purpose of varying the set position of the stopping and releasing device.

The reversible hydraulic motor 23 is connected with two pipe lines 25 and 26 for supplying and exhausting the hydraulic fluid, and the flowing direction of the pres surized fluid is controlled by a four-way electromagnetic valve (not shown) so that the direction of rotation of the hydraulic motor 23 is reversed.

When the upper punch UP is lowered as indicated in FIG. 7 for forming or compacting the powder material, the core rod 2 is also lowered, aind the amount of lowering of the core rod 2 is limited by the distance a shown in FIG. 1. More specifically, the lowering of the core rod 2 also lowers the piston rod 3, and the downward movement of the piston rod 3 is stopped when the circular block 6 fixed to the lower end of the piston rod 3 abuts against the upper surface of the catches 16 of the stopping and releasing device according to the present invention. In this condition, the circular block 6 presses on the catches 16 by a compressive force proportional to the annular surface area of the stepped portion provided near the upper end of the core rod 2.

After the completion of the formation of the powder material, the upper punch UP is elevated as indicated in FIG. 8, and the compressive force applied to the powder material is thereby released. As a result, the depression force acting between the circular block 6 and the upper surface of the catches 16 is reduced to a value corresponding to a mere residual stress in the powder material. Under this condition, the oscillatable cam 20 can be easily driven by the motor 23, and the releasing catches 16 are retracted in radial directions, so that the diameter of the inner bore formed by the inwardly facing Walls of the rising portions 16a of the catches 16 is expanded or enlarged.

If, at this instant, compressed air is supplied into the upper chamber of the cylinder 5, the piston rod 3 and the circular block 6 will be further lowered through a distance b corresponding to the depth of the inner bore formed by the plurality of catches 16 (see FIG. 9).

The above described step formed on the core rod 2 near the upper end thereof is employed for determining the depth of an inner bore provided in the formed powder material S. For this reason, the stopped position of the piston rod 3 must be adjusted to suit the desired measurement of the formed powder material S.

This can be achieved by rotating a shaft 33, for instance, by means of a handle (not shown) attached thereto. With the rotation of the shaft 33, bevel gears 32 and 31 are rotated. The rotation of the bevel gear 31 rotates the shaft 14, and a pinion 30 ffixed on the lower end of the shaft 14 is thereby rotated. Thus, an adjusting ring 29 having a gear portion on the upper circumference thereof is rotated by the pinion 30, and through the screw threaded portion provided on the inner surface of the adjusting ring 29 and engaging with the threaded portion provided on the outer surface of an adjustable mounting disc 28 for the oscillatable cam 20 and the plurality of catches 16, the adjustable mounting disc 28 is raised or lowered for adjusting the vertical position of the stopping and releasing device. It should be noted that an extension arm 27 is also provided on one side of the upper portion of the adjustable mounting disc 28, and a hole provided in the extension arm receives the shaft 14 slidably inserted therethrough, so that the rotation of the adjustable mounting disc 28 around its axis is prevented. With the above described construction, the stopping and releasing positions of the device according to the present invention can be adjusted within a range designated by the distance 0 indicated in FIG. 1.

As is apparent from the above description, since the stopping position and the releasing position of the core rod 2 are determined by closing and expanding the diameter of the inner bore formed by the catches 16 through radial movement of the latter, stopping and releasing of the core rod 2 can be easily achieved. Furthermore, because the driving shaft of the hydraulic motor and the oscillatable cam 20 are coupled through a spline engagement, the hydraulic motor can be fixed to a frame bracket of the casing, and the possibility of oil leakage from the junction portions of the motor and the pipe lines can be substantially eliminated. In addition, since the oscillatable cam is inserted within the space formed between the releasing catches 16 and the adjustable mounting disc 28 with ample marginal gaps therebetween, the oscillatable cam can be freely moved even in the case when the powder material is compressed and the core rod 2 is urged toward the releasing catches 16, and no harmful effect is imparted to the operation of the hydraulic motor spline coupled to the oscillatable cam 20.

We claim:

1. In a powder compacting and forming press having a die and a displaceable core rod for forming workpieces from powders, a stop and release device comprising a plurality of wedge blocks having upstanding portions capable of withstanding the load on said rod during a forming operation, said upstanding portions having opposed surfaces configured in cross section for defining a bore coaxial with said rod, displacement means for selectively displacing said wedge blocks inwardly and outwardly radially of the axis of said bore for varying the cross section dimension of said bore and positioning the upstanding portions relative to said axis so that the transverse dimension of said bore is less than the transverse dimension of said rod so that said rod rests on said upstanding portions during a forming operation and positioning the upstanding portions so that the bore is dimensioned to allow said rod to center axially thereinto for release of the rod subsequent to a forming operation, said displacement means comprising, an oscillatable cam having spirally configured camming grooves, cam followers on said wedge blocks coactive with respective ones of said grooves, and reversible drive means for selectively oscillating said cam in opposite directions for displacing said wedge blocks radially inwardly and outwardly relative to said axis.

2. In a powder compacting and forming press having a die and a displaceable core rod for forming workpieces from powders, a stop and release device according to claim 1, in which said wedge blocks comprise portions extending therefrom defining the bottom of said bore to determine the maximum axial depth of said bore and thereby limit the maximum axial entry of said rod in said bore.

3. In a powder compacting and forming press having a die and a displaceable core rod for forming workpieces from powders, a stop and release device according to claim 1, mount means mounting said wedge blocks and oscillatable cam for movement upwardly and oscillatable cam downwardly and upwardly and relative to said drive means.

4. In a powder compacting and forming press having a die and a displaceable core rod for forming workpieces from powders, a stop and release device according to claim 3, in which said oscillatable cam has an axial bore having an inner spline, said drive means having a spline shaft in the splined bore of said cam to allow relative movement axially of said drive shaft, said mount means having a threaded portion, and means cooperative with the threaded portion for variably positioning said mount means upwardly and downwardly at different positions.

References Cited UNITED STATES PATENTS 3,172,156 3/1965 Belden 18-16.7 3,168,759 2/1965 Johannigman 18-16] 3,132,378 5/1964 Johannigman 18-16 R I. HOWARD FLINT, JR., Primary Examiner US. Cl. X.R. 18-465 

